Calxeda, Intel and other chip vendors said they'll design a common CPU slot for x86 and ARM processors

Facebook's Open Compute Project is being expanded to incorporate ARM processors, providing new options for companies shopping for low-cost hardware to build out cloud computing environments.

Chip vendors from both the ARM and x86 sides of the house announced they are working together to develop a "common slot architecture" that will allow ARM and x86 processors to coexist side by side on the same motherboard.

The common slot design, which Facebook also jokingly calls a "group hug board," is being backed by x86 vendors Intel and Advanced Micro Devices, as well as ARM vendors AppliedMicro, Calxeda and Tilera.

The announcements were made at the fourth Open Compute Project Summit, which kicked off Wednesday in Silicon Valley. At the same event, Facebook announced an additional, very low-cost server design for running databases. Its previous efforts were aimed at Web servers.

And Intel announced that it is submitting technology for silicon photonics networking to the project, which will allow for the design of server racks with interconnects as fast as 100Gb per second, providing extremely low latency rates.

Facebook began the Open Compute Project abut 18 months ago, with the goal of designing highly modularized servers that give customers more control over the networking, processor, memory, power supplies, management software and other components that go into their servers.

"Consumers are smart, we know what we need, we know what we want, we see the current and future challenges," said Frank Frankovsky, Facebook vice president of hardware design and supply chain operations, who opened the event.

The idea is that end customers, such as large financial institutions, will be able to design servers that match the workloads they need, at an affordable price, by selecting from the various standardized modules developed by the participants.

They would order their servers through systems integrators, who would then work with Taiwanese server vendors such as Quanta to manufacture the systems.

The model is seen by some as a threat to traditional server vendors such as Hewlett-Packard and Dell, although those companies are also members of the Open Compute Project and say they will offer servers that incorporate the designs.

ARM processors are widely used in smartphones because of their low power consumption, and they're now being eyed for certain server workloads as well, those where the brawn of a more power-hungry Intel or AMD x86 chip isn't required.

Developing a common slot architecture fits with the goal of reusing as many of the server building blocks developed by the Open Compute Project as possible. The specification will define a processor card, including the CPU, memory and required chipsets, that can then slot into one of the project's motherboard designs.

"The processor card will be able to support any type of system-on-chip, and it will plug into a backplane that allows you to expand the system out to include a cluster of cards," said Gina Longoria, product marketing director for Calxeda.

The specification still needs to be built out, and no timeframe for it was given Wednesday. But Frankovsky held aloft a server board that he said contained five x86 processors from Intel and five 64-bit ARM processors from AppliedMicro.

AppliedMicro also announced that it has submitted the first 64-bit ARM-based server specification to the Open Compute Project, based on its upcoming X-Gene server board.

James Niccolai covers data centers and general technology news for IDG News Service. Follow James on Twitter at @jniccolai. James's e-mail address is james_niccolai@idg.com